In this study, we investigated whether the phenotypic difference observed between two lattice corneal dystrophy type 1 (LCD type 1) cases caused by either a single A546D substitution or an A546D/P551Q double substitution in TGFBIp (transforming growth factor beta induced protein) can be ascribed to (i) a difference in the proteomes of corneal amyloid deposits, (ii) altered proteolysis of TGFBIp, or (iii) structural changes of TGFBIp introduced by the P551Q amino acid substitution.
Two mutations in the TGFBI gene (A546D and P551Q) cosegregated with LCD in an extensively studied family that lacked the R124C mutation that frequently accompanies this form of corneal amyloidosis.